96 nanomaterials nanorod

One-dimensional (ID) nanomaterials nanorods, nanowires, nanotubes, and nanospindles... 

The alternation of temperature in a hydrothermal reaction was demonstrated to be crucial in changing the crystal phases or morphologies of nanomaterials. In the case of K2Cr207, when the reaction temperature was increased to 180 °C, K-OMS-2 microspheres consisting of nanoneedles were synthesized in contrast to the nanoduster arrays composed of tetragonal prism nanorods synthesized at 120 °C (Figure 8.1a-c). In the case of Na2Cr207, when the reaction temperature was 100 °C, Na-OMS-2 phase was formed. However, when the reaction temperature was... 

The various methods of preparation employed to prepare nanoscale clusters include evaporation in inert-gas atmosphere, laser pyrolysis, sputtering techniques, mechanical grinding, plasma techniques and chemical methods (Hadjipanyas Siegel, 1994). In Table 3.5, we list typical materials prepared by inert-gas evaporation, sputtering and chemical methods. Nanoparticles of oxide materials can be prepared by the oxidation of fine metal particles, by spray techniques, by precipitation methods (involving the adjustment of reaction conditions, pH etc) or by the sol-gel method. Nanomaterials based on carbon nanotubes (see Chapter 1) have been prepared. For example, nanorods of metal carbides can be made by the reaction of volatile oxides or halides with the nanotubes (Dai et al., 1995). 

The simplest way to classify nanomaterials used in combination with liquid crystal materials or the liquid crystalline state is by using their shape. Three shape families of nanomaterials have emerged as the most popular, and sorted from the highest to the lowest frequency of appearance in published studies these are zero-dimensional (quasi-spherical) nanoparticles, one-dimensional (rod or wirelike) nanomaterials such as nanorods, nanotubes, or nanowires, and two-dimensional (disc-like) nanomaterials such as nanosheets, nanoplatelets, or nanodiscs. 

The aforementioned frequency of the use of these nanomaterial shapes is best attributed to two factors (1) the ease with which these nanoparticle shapes can be synthesized in the laboratory and (2) the availability of these nanomaterials from commercial sources. It cannot be the aim of this review to cover all of the different nanomaterials used so far, but some of the most commonly investigated will be introduced in more detail. For zero-dimensional nanoparticles, emphasis will be put on metallic nanoparticles (mainly gold), semiconductor quantum dots, as well as magnetic (different iron oxides) and ferroelectric nanoparticles. In the area of onedimensional nanomaterials, metal and semiconductor nanorods and nano wires as well as carbon nanotubes will be briefly discussed, and for two-dimensional nanomaterials only nanoclay. Finally, researchers active in the field are advised to seek further information about these and other nanomaterials in the following, very insightful review articles [16, 36-45]. 

Beneficial electro-optic effects have also been reported for semiconductor quantum dots doped into nematic liquid crystals. Khoo and Mallouck et al. published one of the earlier reports on suspensions of quantum dots in nematic liquid crystals [331], This work, however, focused on CdSe nanorods and will be discussed in a later section on two-dimensional nanomaterials in liquid crystals. 

With the advent of nanomaterials, different types of polymer-based composites developed as multiple scale analysis down to the nanoscale became a trend for development of new materials with new properties. Multiscale materials modeling continue to play a role in these endeavors as well. For example, Qian et al. [257] developed multiscale, multiphysics numerical tools to address simulations of carbon nanotubes and their associated effects in composites, including the mechanical properties of Young s modulus, bending stiffness, buckling, and strength. Maiti [258] also used multiscale modeling of carbon nanotubes for microelectronics applications. Friesecke and James [259] developed a concurrent numerical scheme to evaluate nanotubes and nanorods in a continuum. 

While Au nanorods and other NIR-active nanoparticles have untapped potential for clinical in vivo imaging applications, the focus at present is on preclinical in vitro studies to better ascertain the biological effects of these nanomaterials. Surface chemistry becomes a critical issue, as it determines the biocompatibility, dispersion stability, and site-directed targeting of nanoparticles. For example, Au nanorods coated with cetyltrimethylammonium bromide (CTAB), a cationic surfactant used during nanorod synthesis, are internalized by KB cells via a nonspecific uptake pathway within hours of its addition to the culture medium, and transported toward the... 

A novel and simple one-step solid-state reaction in the presence of a suitable surfactant (PEG-400) has been developed to synthesize uniform polyoxometalate nanorods with an average diameter of ca. 20 nm and a length of up to 400 nm. Polyoxometalate nanoparticles were also prepared by one-step solid-state reaction at room temperature. The polyoxometalate nanorods and nanoparticles were characterized by IR, elemental analyses, XRD and TEM. The uniform nanoparticles have an average size of 8 10 nm. The possible formation mechanism of these polyoxometalate nanomaterials was speculated. 

Element analyses results prove that these nanoparticles and nanorods still keep the compositions of POMs. In the IR spectra, intense bands at 1089, 956, 913, 797 cm are attributed to the vibration of v (P=Oa), v (W=Ot), v (W-Ob-W) and v (W-Oc-W), respectively. These characteristic peaks of the Dawson type structure further prove that the nanomaterials are composed of POMs. The XRD patterns of POM nanoparticles are shown in Figure 1. The sizes of these POM nanoparticles, 8-10 nm, were calculated from the data of broadened XRD peaks with the Scherer equation D = 0.89 k / P cos 0. As shown in the Figure 2, the uniform nanoparticles have an average size of 8 10 nm and nanorods have average diameter of ca.20nm and lengths of up to 400nm. 

A novel, one-step, solid-state reaction at room temperature was employed to synthesize the POM nanorods at ambient temperature, using PEG-400. It has been known that the surfactant PEG forms a chainlike structure due to the assembly in water. [30] Therefore, we can imagine that ID nanomaterials could be formed in the field of the chainlike structure of PEG. During the preparation of ID POM nanomaterials, the sticky solution is one of important factors, in which the uniform POM nanorods could be obtained and stably exist without agglomeration. 

Although such a variety of synthetic methods can be used to produce ZnO nanomaterials, the following section will provide an overview of synthetic procedures to produce ZnO nanomaterials that are further demonstrated for fluorescence detection of biomolecules [61-65], Specifically, the following section will focus on a gas-phase nthetic route exploiting microcontact-printed catalysts and describe an in situ m od for producing ZnO nanorod (ZnO NR) platforms in an array format The physical and optical properties of as-synthesized ZnO NRs will be also discussed. 

This experimental investigation focuses on the preparation of polycrystalline magnesium oxide nanorods via capillary-driven infiltration of a precursor solution into the cylindrical pores of a track-etched polycarbonate membrane followed by thennal decomposition procedure. The nanomaterial was fully characterized by SEM, EDX,... 

Metallic nanorods are highly interesting materials from many points of view as elements in future nanoscale electronic circuits as sensors as catalysts as optical elements in future nanoscale optical devices. Gold and silver nanorods have distinct visible absorption and scattering spectra that are tunable with aspect ratio. Many workers have developed wet synthetic routes to these nanomaterials, with control of aspect ratio a key improvement compared to the synthesis of simple nanospheres. Another key area for which improvements need to be made is the understanding of the atomic arrangements of the different faces of crystalline... 

In addition to the size, also the shape of NMs was shown to play a role in induction of toxicity. NMs made of the same material but in different shapes can be differently internalized into the cells, react with cell membranes, and produce different oxidative effects [6, 14]. Carbon nanomaterials with different geometric structures (single-walled carbon nanotubes [SWCNTs], MWCNTs, and fullerenes) were shown to exhibit quite different cytotoxicity and bioactivity in vitro [15]. The uptake of Au nanospheres and nanorods was also significantly different, illustrating the role of the shape on NM internalization [6, 48],... 

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